The present invention relates to an industrial vehicle having a body structure with a counterweight such as a counterbalanced forklift.
The counterbalanced forklift disclosed in, for example, Japanese Laid-Open Patent No. 2000-6624 has a body structure as described below. That is, a rear wheel axle supporting a pair of left and right rear wheels is pivotably supported in a vertical direction with respect to a vehicle body, and a lock cylinder regulating pivoting of the rear wheel axle is supported between a body frame and the rear wheel axle.
Generally, the body frame for the forklift is formed by welding a plurality of plate members. The counterbalanced forklift is provided with voluminous counterweight in the rear of the vehicle body. The rear end of the vehicle frame extends substantially to a position of the rear wheel axle. In the rear of the vehicle body toward the rear of the rear wheel axle, there is arranged a counterweight to be fixed to the rear end of the vehicle frame.
FIGS. 7 to 9 show the body frame 80 of the forklift described in the above-described publication. The body frame 80 has a pair of structures 81a and 81b coupled by a front coupling member 82 and a rear coupling member 83. A first back plate 84 couples rear portions of both structures 81a, 81b with each other. The first back plate 84 is arranged on a plane perpendicular to the fore-and-aft direction of the vehicle.
Each structure 81a, 81b has an extension portion extending toward the rear of the vehicle body. Both extension portions are coupled to each other with a second back plate 85 arranged in parallel with the first back plate 84. Each extension portion is provided with a hanger portion 86 for detachably supporting the counterweight.
The body frame 80 is provided with an axle supporting portion 87 for supporting the rear wheel axle. The axle supporting portion 87 extends from the rear surface of the fist back plate 84 toward the rear, and is coupled with the rear surface of the first back plate 84 and the lower end of the second back plate 85 (see FIG. 8).
Weight of the counterweight supported by both hanger portions 86 is applied to the axle supporting portion 87 via the second back plate 85, and further is applied to both rear wheels from the rear wheel axle supported by the axle supporting portion 87.
As shown in FIG. 9, the body frame 80 has a coupling portion 90 for supporting the lock cylinder 89. The lock cylinder 89 is provided between the coupling portion 90 and the rear wheel axle 88. The coupling portion 90 includes the second back plate 85, an installation plate 91 provided in the rear thereof, and a coupling shaft 92 for supporting the upper end portion of the lock cylinder 89. The lock cylinder 89 is supported by the coupling shaft 92 in the fore-and-aft direction of the vehicle.
For example, when the vehicle abruptly turns, an expansion/contraction operation of the lock cylinder 89 is inhibited, and as a result, pivoting of the rear wheel axle 88 with respect to the body frame 80 is inhibited, and any inclined movement of the vehicle is limited. Since a powerful force is applied to the coupling portion 90 from the lock cylinder 89 at this time, it is necessary to particularly reinforce structural strength of surroundings of the coupling portion 90.
Thus, the second back plate 85 and the installation plate 91 have been made thicker than other plate members constituting the body frame 80, or reinforcement has newly been welded to the second back plate 85 and the installation plate 91. In these cases, the body frame 80 is complicated in structure.
Also, in addition to the basic structural members of the body frame 80, members for coupling the lock cylinder 89 to the body frame 80 such as the installation plate 91 and the reinforcement are required, and the number of components is increased. Further, since it is necessary to weld these members to the body frame 80 with long weld length, the manufacturing steps are increased.